Battery condition indicators are used in lead/acid storage batteries of many types, including those installed in motor vehicles. Known battery condition indicators function as hydrometers detecting changes in the specific gravity indicative of the electrical charge condition of the battery, and provide a visual indication of the charge condition. Battery condition indicators also can detect changes in the electrolyte level in the battery and provide a visual indication if the electrolyte level is below a predetermined minimum level. It is known to provide both charge condition and electrolyte level detection functions in the same battery condition indicator.
A known battery condition indicator is inserted in an opening through the cover for the cell of a battery and provides a head with a visual window for looking into the indicator. A cage or box is immersed in the fluid electrolyte, if the battery is adequately filled. One or more floatable indicator body is contained in a channel or channels in the cage and responds to different battery conditions to rise or fall in the channels. A light-transmissive rod extends between the head of the indicator and the cage with the floatable bodies. A conical tip at the end of the light-transmissive rod has a tip adjacent the channels in which the one or more floatable bodies move. The floatable bodies are of different colors to provide different visual cues when visible through the indicator. A battery condition indicator having one floatable body can provide visual cues for a satisfactorily charged battery with satisfactory electrolyte level, a different visual cue for a satisfactory electrolyte level but a low battery charge and a third cue if the electrolyte level is low. By providing more floatable bodies responsive to different specific gravities, high and low fluid levels can be indicated as well as low, fair and satisfactory electric charge.
Battery condition indicators as described have worked well, but are not without disadvantages. Installation of the indicator in a battery cover is known use an additional component in the way of a gasket or malleable collar to seal the interface between the indicator and the battery cover opening in which it is installed. The use of multiple components complicates installation. A relatively large hole is required in the battery cover to accommodate the indicator and a separate, independent seal associated with the indicator and the opening in the battery. The requirement for a relatively large opening limits the available locations for the indicator in the battery. Further, if intimate contact is lost along a portion of the seal, contaminate infiltration or leakage can occur. It is known to perform a wash cycle during a late stage in the manufacture of a battery, and wash water can be trapped in small crevices, such as around the indicator. During subsequent battery handling, seepage of the trapped wash water can give an erroneous impression that the battery has leaked, leading to re-testing and/or re-processing the battery.